Regulating electron transfer over asymmetric low-spin Co(II) for highly selective electrocatalysis
Regulating electron transfer over asymmetric low-spin Co(II) for highly selective electrocatalysis
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DOI：
10.1016/j.checat.2021.12.005
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发表时间：
2022-01
期刊：
影响因子：
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通讯作者：
Kuang‐Hsu Wu;Yuefeng Liu;X. Tan;Yangyang Liu;Yang‐Peng Lin;Xing Huang;Yuxiao Ding;Bing-Jian Su-Bing-Ji
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文献类型：
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作者：
Kuang‐Hsu Wu;Yuefeng Liu;X. Tan;Yangyang Liu;Yang‐Peng Lin;Xing Huang;Yuxiao Ding;Bing-Jian Su-Bing-Ji
调节金属有机中心的空间电子构型是调节多相反应，特别是多电子转移反应活性和选择性的关键。在这里，三种不同的不对称金属有机配合物具有独特的空间电子结构固定在纳米碳的电子转移控制的氧还原反应。强场配体诱导的低自旋（LS）CoII通过配体的质子转移能力产生了调节反应选择性所必需的空间构型，其中酸性二胺配体促进四电子转移（94%），而碱性配体驱动高度选择性的两电子路径（97%）。利用X射线吸收光谱、反应动力学路径分析和密度泛函理论计算，研究了催化位点反应选择性的空间电子调控。研究结果表明，CoII的不对称配位LSstate是形成独特的“flytrap”结构以促进O2捕获并进行质子耦合电子转移所必需的，而这一过程受配位体的Brønsted酸性调节.
Modulating the steric-electronic configuration of metal-organic centers is key for tuning the activity and selectivity of heterogeneous reactions, especially multi-electron transfer reactions. Here, three different asymmetric metal-organic complexes with unique steric-electronic structures are immobilized on nanocarbon for an electron-transfer-controlled oxygen reduction reaction. The strong-field ligand-inducedlow-spin(LS) CoIIcreates a necessary steric configuration for regulating reaction selectivity through ligand's proton transfer ability, for which acidic diamine ligands facilitate a four-electron transfer (94%), whereas basic ligands drive a highly selective two-electron route (97%). The steric-electronic regulation of the reaction selectivity at catalytic sites is characterized using X-ray absorption spectroscopy, reaction kinetic path analysis, and density functional theory calculation. Our results indicate that anLSstate of CoIIwith asymmetric coordination is necessary to form a unique "flytrap" structure to promote O2capture for the subsequent proton-coupled electron transfer, which is regulated by the Brønsted acidity of coordinating ligands.